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  • 1
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 10 (1987), S. 484-492 
    ISSN: 0935-6304
    Schlagwort(e): Capillary GC ; Extract concentration ; Kuderna-Danish concentration ; Whole column cryotrapping ; Trace analysis ; PCBs ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Many solvent extracts must be concentrated prior to analysis. Both Kuderna-Danish (K-D) concentration and inert gas blowdown are commonly used. Significant losses often occur with the latter. Solvent removal/thermal desorption (SRTD) on a precolumn was investigated here as an alternative or supplement to these methods. The compounds studied included polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs). SRTD was carried out by injecting 100 μL of extract into a cartridge-type precolumn, selectively volatilizing the solvent with a stream of carrier gas, then thermally desorbing the analytes to a fused silica capillary gas chromatography (GC) column. The mean total recoveries and mean standard errors obtained were 109 and ±12%, respectively. SRTD was found to give sharper peaks than were obtainable with on-column injection. Method detection limits accessible for PCBs by capillary GC with electron impact mass spectrometry with the assistance of SRTD were estimated. Overall, SRTD was found to be an effective, rapid, high recovery concentration method for solvent extracts.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 7 (1984), S. 504-508 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Fused silica capillary columns ; GC/MS/DS ; Cryotrapping and cryofocussing of organics ; Purgeable compound analysis ; Trace organic analysis ; Priority pollutants ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The purge and trap (P&T) method of analysis has been interfaced with fused silica capillary column gas chromatography. This interfacing has been accomplished without splitting the P&T trap desorption carrier gas. Thus, 100% of the purged compounds are transferred to the column. The analytes are cryofocussed on the column using whole column cryotrapping (WCC) at -80°C. The resulting P&T/WCC procedure is extremely well-suited to the analysis of trace purgeable aqueous organic compounds. Samples and standards containing a variety of aromatic standard compounds were analyzed. The standards included benzene, toluene, ethylbenzene, xylenes, C3-C4-benzenes, and naphthalene, as well as three P&T internal standard compounds. Chromatographic peak widths were uniformly less than 6 s at the base and excellent precision was obtained in the relative retention time data for all compounds. The chromatogram of a groundwater sample contaminated with aromatic gasoline compounds is also presented. Since P&T/WCC works well with fused silica capillary columns, the full sensitivity and chromatographic efficiency of capillary gas chromatography is made available to P&T analyses.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 10 (1987), S. 617-619 
    ISSN: 0935-6304
    Schlagwort(e): Capillary gas chromatography ; Mass spectrometry ; Fused silica ; CC/MS ; GC/MS interface ; Open split interface ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 292-299 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Fused silica capillary columns ; GC/MS/DS ; Cryotrapping of organics ; Cryofocusing of organics ; Trace organic analysis ; Priority pollutants ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A 30 m, 0.25 mm ID, fused silica capillary column at temperatures from -60 to -100°C has been shown to be a quantitative trap for organic compounds with volatilities ranging from that of 1, 1 -dichloroethene that of chlorobenzene. This type of “whole column cryotrapping” provided sharp peaks (peak width approximately 4-7 seconds) for all compounds at a trapping temperature of -80°C and with high carrier gas pressures and linear velocities (30 psi and 110 cm/s, respectively). Whole column cryotrapping possesses great simplicity, chromatographic efficiency (no trapping loop connections), and a built-in indicator of quality assurance for trapping efficiency (i.e., peak shape). These advantages are extremely attractive and are indicative of the fact that the potential of this approach has not yet been fully appreciated.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 7 (1984), S. 597-598 
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 9 (1986), S. 18-29 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography, GC ; Fused silica capillary columns ; Mass spectrometry ; Purge and trap ; Purgeable compound analysis ; Trace organic analysis ; Priority pollutants ; Cryotrapping of organic compounds ; Cryofocusing of organic compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The effects of trapping temperature and column film thickness were investigated with respect to their ability to promote effective cryofocusing on fused silica capillary columns. The study was a further development of the purge and trap with whole column cryotrapping (P&T/WCC) method. The rates at which compounds could be thermally desorbed from a P&T unit and transferred to a column (with zero split) were first examined. A near quantitative transfer of the desorbable analytes was obtained with a 4 min, 180°C, 20 mL/min desorption. The compounds tested included naphthalene. Columns with film thicknesses from 0.12 to 3.0 μm were then investigated in P&T/WCC analyses with WCC temperatures ranging from -80 to 0°C. The trapping took place from a transfer line gas stream initially at 175°C. The volatilities of the compounds examined varied from that of 1,1-dichloroethene to 1,1,2,2-tetrachloroethane. A higher film thickness was found to ease the WCC temperature requirements. Within each column type, the warmest WCC temperatures which allowed good cryotrapping with no significant increases in peak width were: 0.25 μm, -70°C; 1.0 μm, -50°C; 3.0 μm, -20°C. In addition to being quantitative, the trapping provided good chromatography.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 10 (1987), S. 409-410 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary GC ; Mass spectrometry ; Purge and trap ; Purge with whole column cryotrapping ; Whole column cryotrapping ; Purgeable compound determination ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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